Self charging nuclear battery



1965, M. M. GOLDSTEIN ETAL 3,200,269

SELF CHARGING NUCLEAR BATTERY Filed Jan. 31. 1961 STROA/ T/UM 90 INVENTORS, Melvin. G nlcfsc Ein BY Harry E. L151] 1 1 fimoa am a. 92

United States Patent M 3,200,269 SELF CHARGING NUCLEAR BATTERY Melvin M. Goldstein, Yonkers, and Harry C. Lieb, Rockville Centre, N.Y., assignors, by mesneassignrnents, to

the United States of America as represented by the Secretary of the Army Filed Jan. 31, 1961, Ser. No. 86,268 2 Claims. (Cl. 3103) This invention relates to a power source and more particularly to a nuclear battery of the self charging type utilizing strontium 90 as the radioactive isotope.

The present invention has wide range of uses such as for example, in the superquick, delay, or selectable electrical circuits of fuzes, timers and the like and consists of a brass housing, a housing insert of aluminum alloy, a bronze contact pin molded in a thermoplastic resin, e.g. polystyrene plug, a brass insulator cap with an aluminum alloy insert and an electron emitter (source of beta rays) consisting of .1 cc. of strontium 90 solution placed in the bottom of the housing and evaporated in place with a minute quantity of binder solution, and a shorting clip.

The power source of this invention is designed to give, at the end of a 20-year storage period, a minimum output current of 4.5 micromicroamperes at a minimum voltage level of 300 volts. The output current at other times within this 20 year shelf life will be greater as a result of less radioactive isotope decay having taken place. The equilibrium voltage, in the unshorted condition, is a minimum of 2000 volts and is reached within 16 hours at any temperature between 65 F. and +160 F. Radiation from this power source will be no more than 0.5 milliroentgens per hour at a distance of 6 inches.

It is a primary object of this invention to provide a power source utilizing strontium 90 as the radioactive isotope.

It is another object to provide a power source having a life of approximately 20 years in which the radioactive isotope decay is minimized.

It is still another object of the invention to provide a power source having a wide range of uses in the electric circuits of fuzes, timers, etc.

With these and other objects in view which will become apparent as the specification develops, reference is made to the drawing forming a part of the specification, wherein:

FIG. 1 is an axial sectional view taken through the power source of the invention; and,

FIG. 2 is a top plan view of the device.

Referring more particularly to the drawing, 1 indicates generally the power source and consists of a brass cupshaped housing 2. An aluminium alloy insert 3 is fitted snugly into housing 2 and an outer cup shaped member 4 of synthetic resinous type material is positioned into insert 3.

An electron emitter is placed in the outer member 4 as at 5. The emitter is composed of strontium 90 and is received as the chloride in a hydrochloric acid solution, .1 cubic centimeter of the final solution is placed into the housing assembly and a minute quantity of a binder solution is added and evaporated to dryness slowly to prevent spatteriug.

The binder solution consists of equal volumes of a 5% by weight of a polyvinyl alcohol solution and a normal sodium hydroxide solution.

A plug assembly, indicated generally by 6, is fitted into the housing assembly and consists of a Phosphor bronze pin 7 molded into a body 8 of highly thermoplastic resin.

, Patented Aug. 10, 1965 Both thehousing insert 3 and the outer member 4 are shorter than housing 2 as best seen in FIG. 1, the member 4 being shorter even than housing insert 3 for the purpose of ease of assembly. Body 8 defines an annular flange 9 of such height as to be flush with top surface of housing insert 3 when assembled.

Body 8 is also provided with a reduced integral boss 10 at the upper end thereof.

An aluminium alloy cap insert 11, having an outer diameter equal to the outer diameter of housing insert 3 and a central bore 12, is fitted around boss 10. A brass cap 13, of the same diameter as cap insert 11 and provided with a central bore 14, is fitted around boss 10 and over insert 11 and completes the plug assembly.

The rim of housing 2 is crimped as at 15 to fasten cap inset 11 and cap 13 in snug fitted relation with body 8.

A shorting clip indicated generally by 16 is provided and consists of a ring portion 17 encircling housing 2 and an integral tongue 18 which is perforated as at 19 to receive pin 7.

Pin 7 is provided with a thickened portion 20 to firmly anchor it in the highly thermoplastic mold.

In preparing for use, the shorting clip 16 is removed from the power source 1 by sliding it upward and oh.

In operation, the power source 1 depends upon the electrons emitted from the strontium for its operation. The emitter 5 is in electrical contact with pin 7 which forms the contact button. The housing 2 with the aluminum insert 3 collects the electrons and acts as the other point of electrical contact to complete the circuit. As electrons are negative charges, the housing 2 forms the negative terminal of the power source while the pin 7 forms the positive terminal. The steady voltage level is controlled by the activity of the strontium emitter 5, the power source insulation resistance, the load insulation resistance, and the load resistance.

Certain precautions are required in use, handling and storage.

The clip 16 should be in place at all times when the power source 1 is not in use.

Extreme care should be exercised in handling the power source 1 since oil and/or salt deposits left on the insulators by handling will present leakage paths which will reduce the efiiciency of the unit.

All precautions for storage and handling of radioactive material with a radiation level of 0.5 milliroentgen per hour at a distance of 6 inches and as high as 30 milliroentgens per hour at a distance of 0.5 inch (distance for both readings is from center of power source to center of the sensing volume of the measuring instrument).

Variations and modifications may be effected without departing from the scope of the novel concept of the present invention.

What is claimed is:

1. A power source comprising a housing assembly, said housing assembly comprising a cup shaped member, a cup shaped insert in said cup shaped member, a cup shaped member of synthetic resinous type material positioned in said insert, an electron emitter in the bottom of said member of synthetic resinous type material and a plug assembly in said housing assembly, said plug assembly comprising a centrally disposed pin having a thickened portion thereon, said pin adapted to contact said emitter, a highly thermoplastic body molded about said pin and positioned in said member of synthetic resinous type material, an insert surrounded by said housing assembly, a cap on said insert and a shorting clip detachably mounted on said housing assembly and releasably engaging said pin.

tion placed in said housing.

References Cited by the Examiner UNITED STATES PATENTS 2,774,891 12/56 Dziedziula et a1 3103 2,775,730 12/56 Eilenberger et a1 320-1 2,930,909 3/60 Lieb 3103 10 FOREIGN PATENTS 8/55 Great Britain.

OTHER REFERENCES Coleman: Nucleonics, December 1953; vol. 11, pages 42-45 (TK9001 N8).

CHESTER L. JUSTUS, Primary Examiner.

FREDERICK M. STRADER, LEWIS H. MYERS,

Examiners. 

1. A POWER SOURCE COMPRISING A HOUSING ASSEMBLY, SAID HOUSING ASSEMBLY COMPRISING A CUP SHAPED MEMBER, A CUP SHAPED INSERT IN SAID CUP SHAPED MEMBER, A CUP SHAPED MEMBER OF SYNTHETIC RESINOUS TYPE MATERIAL POSITIONED IN SAID INSERT, AN ELECTRON EMITTER IN THE BOTTOM OF SAID MEMBER OF SYNTHETIC RESINOUS TYPE MATERIAL AND A PLUG ASSEMBLY IN SAID HOUSING ASSEMBLY, SAID PLUG ASSEMBLY COMPRISING A CENTRALLY DISPOSED PIN HAVING A THICKENED PORTION THEREON, SAID PIN ADAPTED TO CONTACT SAID EMITTER, A HIGHLY THERMOPLASTIC BODY MOLDED ABOUT SAID PIN AND POSITIONED IN SAID MEMBER OF SYNTHETIC RESINOUS TYPE MATERIAL, AN INSERT SURROUNDED BY SAID HOUSING ASSEMBLY, A CAP ON SAID INSERT AND A SHORTING CLIP DETACHABLY MOUNTED ON SAID HOUSING ASSEMBLY AND RELEASABLY ENGAGING SAID PIN. 